26" wheels weigh less and have less air drag, because they disturb less of the air around them. Great for drafting.
The shorter spokes and smaller diameter rim make it a MUCH stronger wheel. Get 1.5 or smaller profile tires. I feel I get the best roll with 26x1.5
road clearance is high, consider that bigger wheels will get you more clearance, wich would put you further from the ground. Wich would created more drag from the wind (you go slower).
The geometry is upright wich is not great but with some drops you can get as low as you want.
You will be surprised how fast these things go.